Image forming apparatus, control method of image forming apparatus, and non-transitory recording medium

1. An image forming apparatus comprising: a main CPU that starts a predetermined process in response to a turn-off operation on a main power switch of the image forming apparatus; and a sub CPU that controls supply of power to individual units of the image forming apparatus on a basis of a command from the main CPU, wherein the sub CPU: performs regular communication with the main CPU after the turn-off operation, monitors the operating state of the main CPU using the regular communication, and stops supply of power to the individual units when the regular communication is not performed for a monitoring timer value for a predetermined period if a power supply stop command from the main CPU is not received after the turn-off operation, wherein: the regular communication includes periodic notifications from the main CPU to the sub CPU concerning an apparatus state of the image forming apparatus; and the sub CPU resets the monitoring timer value if the sub CPU receives data in the regular communication.

2. The image forming apparatus according to claim 1 , wherein: the sub CPU stops supply of power to the individual units when a communication interface between the main CPU and a predetermined device included in the image forming apparatus does not operate for the predetermined period after the turn-off operation.

3. The image forming apparatus according to claim 1 , wherein: the sub CPU stops supply of power to the individual units when a response to a communication request for checking for an alive state transmitted from the sub CPU to the main CPU should not be returned from the main CPU in the predetermined period after the turn-off operation.

4. The image forming apparatus according to claim 1 , wherein: during the predetermined process, in a normal state, the main CPU stops supply of power to a plurality of devices of the image forming apparatus in a predetermined order.

5. The image forming apparatus according to claim 4 , wherein: the sub CPU receives a predetermined control list defining a power-off order related to the plurality of devices, from the main CPU, in advance, before the turn-off operation.

6. The image forming apparatus according to claim 1 , wherein: when, on the basis of a notification of the state of the main CPU transmitted from the main CPU to the sub CPU, that a condition that the main CPU is in a power-on state is satisfied, the sub CPU performs a forced turn-off control.

7. The image forming apparatus according to claim 1 , wherein: if the sub CPU determines that a forced turn-off control should be performed, and transmits a communication request for checking for an alive state, to the main CPU, and if it is determined that there is no response to the communication request, the sub CPU performs the forced turn-off control.

8. The image forming apparatus according to claim 1 , wherein: if supply of power to the image forming apparatus is not stopped in the predetermined period after the turn-off operation, the sub CPU performs a forced turn-off control, and the predetermined period is a period set to be longer than a time required for a normal finishing process.

9. A control method of an image forming apparatus, wherein: the image forming apparatus includes: a main CPU that starts a predetermined process in response to a turn-off operation on a main power switch of the image forming apparatus; and a sub CPU that controls supply of power to individual units of the image forming apparatus on a basis of a command from the main CPU, the control method includes: a) performing regular communication with the main CPU after the turn-off operation; b) monitoring the operating state of the main CPU using the regular communication, and c) stopping supply of power to the individual units when the regular communication is not performed for a monitoring timer value for a predetermined period if a power supply stop command from the main CPU is not received after the turn-off operation, wherein: the regular communication includes periodic notifications from the main CPU to the sub CPU concerning an apparatus state of the image forming apparatus; and the sub CPU resets the monitoring timer value if the sub CPU receives data in the regular communication.

10. A non-transitory recording medium storing a computer readable program causing an image forming apparatus, including a main CPU that starts a predetermined process in response to a turn-off operation on a main power switch of the image forming apparatus, and a sub CPU that controls supply of power to individual units of the image forming apparatus on a basis of a command from the main CPU, to perform: a) performing regular communication with a the main CPU after the turn-off operation; b) monitoring the operating state of the main CPU using the regular communication, and c) stopping supply of power to the individual units when the regular communication is not performed for a monitoring timer value for a predetermined period if a power supply stop command from the main CPU is not received after the turn-off operation, wherein: the regular communication includes periodic notifications from the main CPU to the sub CPU concerning an apparatus state of the image forming apparatus; and the sub CPU resets the monitoring timer value if the sub CPU receives data in the regular communication.